blob: d462b71c6e2b11b48cc1c502d24c1a702948a356 [file] [log] [blame]
/* Copyright (C) 2008-2013 Free Software Foundation, Inc.
Contributed by Richard Henderson <>.
This file is part of the GNU Transactional Memory Library (libitm).
Libitm is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
Libitm is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<>. */
#include "libitm_i.h"
namespace GTM HIDDEN {
// This function needs to be noinline because we need to prevent that it gets
// inlined into another function that calls further functions. This could
// break our assumption that we only call memcpy and thus only need to
// additionally protect the memcpy stack (see the hack in mask_stack_bottom()).
// Even if that isn't an issue because those other calls don't happen during
// copying, we still need mask_stack_bottom() to be called "close" to the
// memcpy in terms of stack frames, so just ensure that for now using the
// noinline.
void __attribute__((noinline))
gtm_undolog::rollback (gtm_thread* tx, size_t until_size)
size_t i, n = undolog.size();
void *top = mask_stack_top(tx);
void *bot = mask_stack_bottom(tx);
if (n > 0)
for (i = n; i-- > until_size; )
void *ptr = (void *) undolog[i--];
size_t len = undolog[i];
size_t words = (len + sizeof(gtm_word) - 1) / sizeof(gtm_word);
i -= words;
// Filter out any updates that overlap the libitm stack. We don't
// bother filtering out just the overlapping bytes because we don't
// merge writes and thus any overlapping write is either bogus or
// would restore data on stack frames that are not in use anymore.
// FIXME The memcpy can/will end up as another call but we
// calculated BOT based on the current function. Can we inline or
// reimplement this without too much trouble due to unaligned calls
// and still have good performance, so that we can remove the hack
// in mask_stack_bottom()?
if (likely(ptr > top || (uint8_t*)ptr + len <= bot))
__builtin_memcpy (ptr, &undolog[i], len);
GTM_LB (const void *ptr, size_t len)
gtm_thread *tx = gtm_thr();
tx->undolog.log(ptr, len);
} // namespace GTM
using namespace GTM;
/* ??? Use configure to determine if aliases are supported. Or convince
the compiler to not just tail call this, but actually generate the
same_body_alias itself. */
_ITM_LB (const void *ptr, size_t len)
GTM_LB (ptr, len);
#define ITM_LOG_DEF(T) \
void ITM_REGPARM _ITM_L##T (const _ITM_TYPE_##T *ptr) \
{ GTM_LB (ptr, sizeof (*ptr)); }